如何在同一位置用另一个JPanel替换一个JPanel?

时间:2014-10-02 23:04:20

标签: java swing user-interface jpanel layout-manager

我有一个大约四帧的JFrame。在给定动作之后,我想在同一位置将一个面板替换为另一个面板。我切换它们的方法看起来像这样(this对象是一个扩展JFrame的类):

 public void switchPanel(){
    mainPanel.remove(introPanel);
    mainPanel.add(questionPanel);
    this.repaint();
 }

窗口的原始创建如下所示:

 mainPanel.add(titlePanel);
 mainPanel.add(sidePanel);
 mainPanel.add(introPanel);

2 个答案:

答案 0 :(得分:7)

你问:

  

如何将一个JPanel替换为同一位置的另一个JPanel?

非常容易:使用CardLayout,因为此工具是针对这种情况而构建的。

如果你有以下常数:

public static final String INTRO_PANEL = "intro panel";
public static final String QUESTION_PANEL = "question panel";

并添加了你的JPanel

mainPanel.setLayout(cardLayout);
mainPanel.add(introPanel, INTRO_PANEL);
mainPanel.add(questionPanel, QUESTION_PANEL);

cardLayout.show(mainPanel, INTRO_PANEL);

然后你可以用以下方式交换JPanel:

cardLayout.show(mainPanel, QUESTION_PANEL);

将显示交换所需的全部内容,假设QUESTION_PANEL是在将questionPanel添加到mainPanel时使用的String常量,并且mainPanel使用CardLayout。

例如:

import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;

import javax.swing.*;

public class SwapPanels extends JPanel {
   public static final String INTRO_PANEL = "intro panel";
   public static final String QUESTION_PANEL = "question panel";
   private static final int PREF_W = 500;
   private static final int PREF_H = 400;
   private CardLayout cardLayout = new CardLayout();
   private JPanel introPanel;
   private JPanel questionPanel;
   private Random random = new Random();

   public SwapPanels() {
      introPanel = createPanel("Introduction");
      questionPanel = createPanel("Question");
      setLayout(cardLayout);
      add(introPanel, INTRO_PANEL);
      add(questionPanel, QUESTION_PANEL);

      int delay = 3 * 1000; // show intro for 3 seconds
      new Timer(delay, new ActionListener() {

         @Override
         public void actionPerformed(ActionEvent e) {
            cardLayout.show(SwapPanels.this, QUESTION_PANEL);
            ((Timer) e.getSource()).stop();
         }
      }).start();
   }

   private JPanel createPanel(String title) {
      int rgb = random.nextInt();
      Color color = new Color(rgb);
      JPanel panel = new JPanel(new GridBagLayout());
      panel.setBorder(BorderFactory.createLineBorder(color, 60));
      panel.add(new JLabel(title));
      return panel;
   }

   @Override
   public Dimension getPreferredSize() {
      if (isPreferredSizeSet()) {
         return super.getPreferredSize();
      }
      return new Dimension(PREF_W, PREF_H);
   }

   private static void createAndShowGui() {
      SwapPanels mainPanel = new SwapPanels();

      JFrame frame = new JFrame("SwapPanels");
      frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
      frame.getContentPane().add(mainPanel);
      frame.pack();
      frame.setLocationByPlatform(true);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}

答案 1 :(得分:0)

在remove方法之后,你必须运行所有的validate方法。代码将是这样的:

public void switchPanel(){
    mainPanel.remove(introPanel);
    mainPanel.add(questionPanel);
    mainPanel.validate();
}

我希望有所帮助。萨拉姆